Previous systems relied upon the detection of an asset tracking device, commonly referred to as an “asset tag,” by a detection device. For example, the asset with the tag would pass by the detection device and the detection device would by some detection means detect the “tag” or other identifier attached to the asset. The asset tracking system would know the location of the asset because the system would have knowledge of the location of the detection device.
An asset tracking tag may be or include a radio frequency identifying (RFID) tag or the like attached to the asset. Like a barcode, the RFID tag provides information about or associated with the asset, such as a particular tag identifier. However, as RF technology has advanced, the RF transceivers have become more power efficient and smaller thereby allowing RF transceivers with greater range and computing power to be employed in the asset tracking tags.
With the advances in RF technology comes the problem of increased RF signal traffic within a space as well as increased data processing demands on devices within the space coupled to the data network. In addition, the advanced RF technology brings an expectation of improved accuracy in the determination of asset tag location within a space.
Presently, systems utilize complex and overly complicated computations and require large data sets to provide location determination services. As a result, data network traffic is increased without necessarily providing a corresponding increase in the accuracy of the location estimation.
Asset tracking systems employing radio frequency detection often require the detector(s) to actively engage the tag attached to the asset being tracked. Other examples include more complex asset tracking tags that may communicate with devices within the location in order to update information related to the tag or its location, and report the location of an asset through wireless radio frequency communication. The transmission of position updates and data reporting causes the asset tracking tag to continuously operate in a high power consumption state.
Locations of radio devices (e.g. tags) in an area served by a network of RF beacons having known locations can be estimated by a variety of techniques. Received signal strength of signals transmitted by a tag, a RF beacon, or both may be measured by a tag and/or the RF beacon, and used as a proxy for node-to-tag distance (assuming that all nodes transmit signals of equal strength): the farther away the transmitting tag/node, the lower the received signal strength. Present systems require the transmission of the RSS values as well as additional information for the determination of the location of an asset tag. However, this continuous processing of and transmission of data consumes power and adds traffic to the RF communication channels.